The UCLA-CMCR Animal Core will provide a full service for animal experiments in Projects 1 and 2 and for Pilot Research Projects, as required. The Core is a self-contained, strict barrier facility that breeds and maintains, at a low cost, the highest possible quality mice with a defined microbiological flora. In addition to multiple immune competent and immune deficient strains, it maintains breeding colonies of a wide range of transgenic and knockout mouse strains, including many relevant to radiation damage response pathways and DNA repair. The facility has an AEC cesium source 'en suite'with jigs enabling whole and partial body irradiations to be performed. It has a level II Biohazard facility and is able to accommodate studies on gene transfer, radioisotopes, and pathogens. The CORE will assist investigators in obtaining ARC approval, monitoring compliance and animal health, as well as providing training in animal handling and aseptic procedures. Advice and assistance in the design and performance of radiation experiments and analysis and interpretation of results will be provided. Dr. Schiestl (Project 1) and Dr. McBride (Project 2) both currently use the facility and meet regularly to discuss its resources and the experiments outlined in this CMCR application. This resource will be made available to all members of the UCLA-CMCR, and others outside of UCLA on a recharge basis. This is possible because it is under the direct control of Dr. McBride who has the power to allocate space and resources to the CMCR. The Core brings expertise in the study of many normal tissue responses to radiation, in DNA repair, in genetics, and in immunity. It is a powerful tool that provides a variety of genetic models to address the product potential of agents for prophylaxis, mitigation, and therapy of radiation-induced damage, the pathways that might use, and their potential to enhance radiocarcinogenesis. It will perform a vital function in integrating the projects within the CMCR and standardizing information that is derived from individual experimentation. In so doing, it will give added value to the CMCR.